TW201947039A - Melt component estimation device, melt component estimation method, and method for producing melt - Google Patents

Abstract

A melt component estimation device 1 is provided with: an input device 11 into which measurement information for a refining facility 2, including the results of a measurement of an optical property of a furnace opening part during a blowing processing in the refining facility 2, is to be input; a model database in which a model formula and a model parameter both associated with a blowing processing reaction, including a model formula and a model parameter which represent the relationship between an oxygen efficiency for decarburization and a concentration of carbon in a melt in the refining facility 2, are to be stored; a model calculation section 13b for estimating the concentration of a component of the melt, including the concentration of carbon in the melt, using the measurement information, the model formula and the model parameter; and a model determination section 13a for estimating the concentration of carbon in the melt on the basis of the measurement result to determine a model formula and a model parameter, which are to be employed by the model calculation section 13b, on the basis of the result of the aforementioned estimation.

Description

Molten metal component estimation device, molten metal component estimation method, and manufacturing method of molten metal

The present invention relates to a molten metal component estimating device, a method for estimating a molten metal component, and a method for manufacturing a molten metal, for estimating the component concentrations of molten metal and slag in a refining facility in the iron and steel industry.

In an iron smelter, the component concentration and temperature of the molten and milled iron cast from the blast furnace are adjusted in refining equipment such as pretreatment equipment, converters, and secondary refining equipment. Among them, the converter process is also a process of removing impurities and heating up the molten metal by blowing oxygen into the converter, and plays a very important role in the quality management of steel and rationalization of refining costs. In the converter process, in order to make the carbon concentration in the molten metal when the oxygen is stopped blowing consistent with the carbon concentration in the target molten metal, in the final stage of the blowing process, a relationship indicating the relationship between the decarburization oxygen efficiency and the carbon concentration in the molten metal is used. The model formula generally controls the amount of oxygen supplied or estimates the carbon concentration in the molten metal. The carbon concentration in the molten metal whose decarburization oxygen efficiency starts to decrease is about 0.4 [%] (critical carbon concentration). Therefore, in order to obtain high calculation accuracy, the model calculation is performed at the time when the carbon concentration in the molten metal reaches the critical carbon concentration, or the switching is performed. Models are extremely important. Among them, as long as there is no special statement below, "%" and various flows refer to mass% and the original unit of flow.

Patent Document 1 describes a static control that determines the timing of the measurement of the sub-gun using a model formula or the like calculated from the mass balance before the start of the blowing process; and uses the carbon concentration in the molten metal measured by the sub-gun to indicate melting The model expression of the relationship between the carbon concentration in the metal and the decarburization oxygen efficiency determines the dynamic control of the amount of oxygen to be blown until the carbon concentration in the molten metal becomes the target carbon concentration in the molten metal. The method of injecting the oxygen flow rate to determine the timing of the sub-gun measurement.
[Prior technical literature]
[Patent Literature]

[Patent Document 1] Japanese Patent No. 4679955
[Patent Document 2] Japanese Patent Laid-Open No. 2017-115216

(Problems to be solved by the invention)

However, the method described in Patent Document 1 determines the timing of sub-gun measurement based on a static model. Therefore, with the method described in Patent Document 1, if an error occurs in the calculation of the static model due to a measurement error of the component concentration of the molten metal or an unknown external disturbance in the blowing process, the carbon concentration in the target molten metal cannot be determined. There is a possibility that the sub gun measurement cannot be performed for a sufficient time during dynamic control. In addition, if dynamic control is performed from a state where the carbon concentration in the molten metal is higher than the critical carbon concentration for the time control of the dynamic control, decarburization occurs in a region where the carbon concentration in the molten metal is higher than the critical carbon concentration. The oxygen efficiency does not depend on the carbon concentration in the molten metal, but is affected by the decarburization caused by the reduction of iron oxides in the slag, so there is a possibility that the accuracy of the dynamic control is reduced.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a molten metal component estimation device and a molten metal component estimation method that can estimate the carbon concentration in the molten metal with high accuracy, particularly in the final stage of the blowing process. In addition, another object of the present invention is to provide a method for producing a molten metal capable of producing a molten metal having a desired component concentration with a good yield.

(Means for solving problems)

The molten metal composition estimation device of the present invention is characterized by comprising: an input device that is input with measurement information about a refining facility, and the measurement information includes: measurement of optical characteristics of a furnace mouth portion in a blowing process in the refining facility Results; a model database storing model formulas and model parameters regarding the reaction of the refining process, the model formulas and model parameters including: a model formula representing the relationship between the decarburization oxygen efficiency in the aforementioned refining equipment and the carbon concentration in the molten metal And model parameters; a model calculation section that estimates the component concentration of the molten metal including the carbon concentration in the molten metal using the measurement information and the model formula and the model parameters; and a model determination section that estimates based on the measurement results The carbon concentration in the molten metal determines the model formula and the model parameters used by the model calculation unit based on the estimated result.

The molten metal component estimation device of the present invention is the above-mentioned invention, and the measurement result is characterized by including the intensity change rate of the frequency spectrum due to the reduction reaction of the iron oxide in the slag.

The method for estimating a molten metal composition according to the present invention includes: a model calculation step using: measurement information on a refining facility including measurement results of optical characteristics of a furnace mouth portion in a blowing process in a refining facility; and The model formula and model parameters for the reaction of the blowing process are included, including the model formula and model parameters showing the relationship between the decarburization oxygen efficiency and the carbon concentration in the molten metal in the refining equipment, and the composition of the molten metal including the carbon concentration in the molten metal is estimated. Concentration; and a model determination step, which estimates the carbon concentration in the molten metal based on the measurement result, and determines the model formula and the model parameter used in the model calculation step based on the estimation result.

The method for estimating a molten metal component according to the present invention is the above-mentioned invention, and the measurement result is characterized by including a rate of change in intensity of a frequency spectrum due to a reduction reaction of iron oxide in the slag.

The manufacturing method of the molten metal of this invention is characterized by including the process of adjusting the component concentration of a molten metal to a desired range based on the component concentration of the molten metal estimated using the molten metal component estimation method of this invention.

(Effect of the invention)

With the molten metal component estimation device and the molten metal component estimation method of the present invention, the carbon concentration in the molten metal can be estimated with high accuracy, especially in the final stage of the blowing process. In addition, by the method for producing a molten metal according to the present invention, a molten metal having a desired component concentration can be produced with good yield.

Hereinafter, a molten metal component estimation device and an operation thereof according to an embodiment of the present invention will be described in detail with reference to the drawings.

[Composition]
First, the configuration of a molten metal component estimation device according to an embodiment of the present invention will be described with reference to FIG. 1.

FIG. 1 is a schematic diagram showing a configuration of a molten metal composition estimation device according to an embodiment of the present invention. As shown in FIG. 1, a molten metal component estimation device 1 according to an embodiment of the present invention is a device for estimating the component concentrations of the molten metal 101 and the slag 103 to be processed in the refining facility 2 of the iron and steel industry. Here, the refining facility 2 includes a converter 100, a nozzle 102, and a duct 104. A nozzle 102 is arranged on the molten metal 101 in the converter 100. High-pressure oxygen (top-blown oxygen) is ejected from the front end of the nozzle 102 toward the molten metal 101 below. By the high-pressure oxygen, impurities in the molten metal 101 are oxidized and taken into the slag 103 (blowing process). An upper part of the converter 100 is provided with a duct 104 for exhaust gas guide.

An exhaust gas detection unit 105 is disposed inside the duct 104. The exhaust gas detection unit 105 detects the flow rate of the exhaust gas and components (for example, CO, CO ₂ , O ₂ , N ₂ , H ₂ O, Ar, etc.) in the exhaust gas that are discharged during the blowing process. The exhaust gas detection unit 105 measures the flow rate of exhaust gas in the duct 104 based on, for example, a differential pressure before and after a Venturi tube provided in the duct 104. In addition, the exhaust gas detection unit 105 measures the concentration [%] of each component of the exhaust gas. The flow rate and component concentration of the exhaust gas are measured, for example, at a cycle of several seconds. A signal indicating the detection result of the exhaust gas detection unit 105 is sent to the control terminal 10.

The molten metal 101 in the converter 100 is blown into a stirring gas (bottom-blown gas) through a vent hole 107 formed in the bottom of the converter 100. Stir gas system Ar and other inert gases. The blown stirring gas system stirs the molten metal 101 and promotes the reaction between the high-pressure oxygen and the molten metal 101. The flow meter 108 measures the flow rate of the stirring gas blown into the converter 100. The analysis of the temperature and the component concentration of the molten metal 101 was performed immediately before and immediately after the start of the blowing process. In addition, the temperature and component concentration of the molten metal 101 are measured one or more times during the blowing process, and the supply amount (oxygen supply amount) and speed (oxygen supply) of high-pressure oxygen are determined based on the measured temperature and component concentration. Speed) or the flow rate of the stirring gas (stirring gas flow rate).

The blowing processing control system to which the molten metal composition estimation device 1 is applied includes a control terminal 10, a molten metal composition estimation device 1, and a display device 20 as main constituent elements. The control terminal 10 is constituted by an information processing device such as a personal computer or a workstation, and controls the amount of oxygen supplied, the rate of oxygen supplied, and the flow rate of the agitated gas so that the concentration of the molten metal 101 is within a desired range. The data of the oxygen supply amount, oxygen supply rate, and actual performance value of the stirring gas flow rate.

The molten metal composition estimation device 1 is configured by an information processing device such as a personal computer or a workstation. The molten metal composition estimation device 1 includes an input device 11, a model database (model DB) 12, an arithmetic processing unit 13, and an output device 14.

The input device 11 is an input interface for inputting various measurement results and actual performance information on the refining equipment 2. The input device 11 includes a keyboard, a mouse pointer, a pointing device, a data receiving device, and a graphical user interface (GUI). The input device 11 receives actual performance data, parameter setting values, and the like from the outside, and writes the information to the model DB 12 or sends the information to the calculation processing unit 13. The input device 11 is a measurement result of the temperature and the component concentration of the molten metal 101 before the initiation of the blowing process in the refining facility 2 and in at least one of the blowing processes. The measurement results of the temperature and the component concentration are input to the input device 11 by, for example, manual input by an operator or reading input from a recording medium. Further, actual performance information is input to the input device 11 from the control terminal 10. The actual performance information includes information on the flow rate and component concentration of the exhaust gas measured by the exhaust gas detection unit 105, and information on the optical characteristics of the furnace mouth portion of the converter 100 measured by the spectroscope 106. (Fractal performance of the furnace mouth, information on the optical characteristics of the furnace mouth), information on the amount and speed of oxygen supply, information on the flow of stirring gas, information on the amount of raw materials (main raw materials and auxiliary materials), temperature information on the molten metal 101, etc. .

The model DB 12 is a memory device that stores information on a model expression and a parameter (model parameter) of a blowing process reaction in the refining facility 2. The model formula includes at least a decarburization model formula showing the relationship between the carbon concentration in the molten metal 101 in the middle of the blowing process and the decarburization oxygen efficiency. Here, the decarburization oxygen efficiency means the amount of carbon removed from the molten metal 101 with respect to the unit oxygen amount blown into the converter 100. In addition, the model DB 12 stores various information input to the input device 11 and calculation / analysis results in the processing results obtained by the calculation processing unit 13.

The arithmetic processing unit 13 is an arithmetic processing device such as a CPU, and controls the operation of the entire molten metal composition estimation device 1. The calculation processing unit 13 has functions as a model determination unit 13a and a model calculation unit 13b. The model determination unit 13 a and the model calculation unit 13 b are implemented by, for example, executing a computer program by the arithmetic processing unit 13. The calculation processing unit 13 functions as a model determination unit 13a by executing a computer program for the model determination unit 13a, and functions as a model calculation unit 13b by executing a computer program for the model calculation unit 13b. The calculation processing unit 13 may include a dedicated calculation device or a calculation circuit that functions as the model determination unit 13 a and the model calculation unit 13 b.

The molten metal component estimation device 1 having the above-mentioned structure performs the molten metal component estimation process shown below, and estimates the component concentrations of the molten metal 101 and the slag 103 with high accuracy, especially in the final stage of the blowing process. The operation of the molten metal component estimation device 1 when executing the molten metal component estimation process will be described below with reference to the flowchart shown in FIG. 2.

[Molten metal component estimation process]
FIG. 2 is a flowchart showing a flow of a molten metal component estimation process according to an embodiment of the present invention. The flowchart shown in FIG. 2 starts at the timing when the blowing process has been started, and the molten metal component estimation process proceeds to the process of step S1.

In the process of step S1, the arithmetic processing unit 13 obtains a measurement / analysis value of the molten metal 101. Specifically, the arithmetic processing unit 13 obtains measurement / analysis results obtained by measuring the temperature of the sample of the molten metal 101 and analyzing the components. Thereby, the processing of step S1 is completed, and the molten metal component estimation processing proceeds to the processing of step S2.

In the process of step S2, the calculation processing unit 13 obtains the exhaust gas measurement / analysis information (emission gas information), the furnace mouth part optical characteristic information, and the operation amount information from the control terminal 10. In the ordinary converter blowing operation, the exhaust gas information, the optical characteristic information of the furnace mouth section, and the operation amount information are collected at a certain period. If there is a large time delay between the acquisition time of the operation amount information and the acquisition time of the exhaust gas information, consider the time delay (accelerate the exhaust gas information by the delay time) to create data. In addition, if the measured value and the analysis value contain a lot of noise, a smoothed value such as a moving average calculation may be used to replace the measured value and the analysis value. In addition, the errors included in the measured values of the exhaust gas flow rate and the analysis values of CO and CO ₂ are preferably corrected. Thereby, the processing of step S2 is completed, and the molten metal component estimation processing proceeds to the processing of step S3.

In the process of step S3, the model determination unit 13a determines the model calculation unit 13b to use in the model formula and model parameters of the model DB 12 based on the optical characteristic information of the furnace mouth portion obtained in the process of step S2. Calculated model formula and model parameters. Specifically, in terms of the optical characteristics of the furnace mouth of the converter 100, the wavelength of light emitted by the decarburization reaction caused by the reduction reaction of iron oxide in the slag as shown in the following reaction formula (1) In the frequency band (Spectrum), for example, the maximum value of the luminous intensity in a wavelength band with a wavelength of 550 nm to 650 nm is detected. When the carbon concentration in the molten metal reaches near the critical carbon concentration, it is known that the luminous intensity also decreases because the efficiency of the decarburization reaction described in the following reaction formula (1) decreases.

FeO + C → Fe + CO ... (1)

Therefore, as shown in FIG. 3 (a), the model determination unit 13a calculates the change rate of the maximum value of the luminous intensity (the change rate of the luminous intensity), and changes the luminous intensity change rate from a positive value to a negative value as the molten metal. The timing of the middle carbon concentration reaching the critical carbon concentration is detected. Next, the model determination unit 13a is a region where the carbon concentration in the molten metal is higher than the critical carbon concentration, and the model DB12 selects a mass balance calculation formula based on the exhaust gas information and the operation amount information or a physical reaction model based on the operation amount information. Calculation formula and model parameters and model parameters. On the other hand, after the time when the carbon concentration in the molten metal reaches the critical carbon concentration, as shown in FIG. 3 (b), the decarburization oxygen efficiency enters a region that depends on the carbon concentration in the molten metal. Therefore, the model determining unit 13a The decarburization model formula and its model parameters are selected in the model DB12. However, in the present invention, the form of the model formula selected by the model DB 12 is not limited. In addition, as for the method of switching the model, a method of changing the contribution of the decarburization model to the calculation of the model in accordance with the change of the model parameter may be used. Thereby, the processing of step S3 is completed, and the molten metal component estimation processing proceeds to the processing of step S4.

In the process of step S4, the model calculation unit 13b uses the model formula and model parameters determined (selected) in the process of step S3 to calculate the component concentration of the molten metal 101 including the carbon concentration in the molten metal, and will calculate Information on the calculated component concentration of the molten metal 101 is output to the output device 14. The details of the method for calculating the component concentration of the molten metal 101 are described in, for example, Patent Document 2. Thereby, the processing of step S4 is completed, and the molten metal component estimation processing proceeds to the processing of step S5.

In the process of step S5, the arithmetic processing unit 13 determines whether the blowing process has ended. As a result of the determination, if the blowing process has ended (step S5: Yes), the arithmetic processing unit 13 ends a series of molten metal component estimation processes. On the other hand, if the blowing process is not completed (step S5: No), the arithmetic processing unit 13 returns the molten metal component estimation process to the process of step S2.

As is clear from the above description, in the molten metal component estimation process according to an embodiment of the present invention, the model determination unit 13a estimates the carbon concentration of the molten metal 101 based on the optical characteristic information of the furnace mouth portion, and determines the model calculation unit based on the estimation result. The model formula and model parameters used in 13b. More specifically, the model determination unit 13a detects the timing when the carbon concentration of the molten metal 101 has reached the critical carbon concentration based on the optical characteristic information of the furnace mouth portion, and the timing when the carbon concentration of the molten metal 101 has reached the critical carbon concentration. The model formula and model parameters used by the model calculation unit 13b are switched to the model formula and model parameters based on the relationship between the carbon concentration in the molten metal and the decarburization oxygen efficiency. This makes it possible to estimate the carbon concentration of the molten metal 101 with high accuracy, especially in the final stage of the blowing process.

Although the embodiment to which the invention made by the present inventors is applied has been described above, the present invention is not limited by the description and drawings forming part of the disclosure of the present invention made by this embodiment. For example, in the present embodiment, the model switching in the estimation calculation of the carbon concentration in the molten metal is described. However, as shown in the method described in Patent Document 1, control using a static model and a dynamic model can be performed according to the furnace mouth. The optical characteristics measurement information of each part is obtained by the model DB12, and the dynamic model control is performed at an appropriate timing. As described above, according to this embodiment, other embodiments, examples, and operating techniques performed by those skilled in the art in the field are all included in the scope of the present invention.

[Industrial availability]

According to the present invention, it is possible to provide a molten metal component estimation device and a molten metal component estimation method that can estimate the carbon concentration in the molten metal with high accuracy, particularly in the final stage of the blowing process.

1‧‧‧ Molten metal composition estimation device

2‧‧‧ Refining equipment

10‧‧‧Control terminal

11‧‧‧ input device

12‧‧‧ model database (model DB)

13‧‧‧Operation Processing Department

13a‧‧‧Model decision department

13b‧‧‧Model Calculation Department

14‧‧‧Output device

20‧‧‧ display device

100‧‧‧ converter

101‧‧‧ Molten Metal

102‧‧‧ Nozzle

103‧‧‧ Slag

104‧‧‧ Catheter

105‧‧‧Exhaust gas detection department

106‧‧‧ Beamsplitter

107‧‧‧ Vent

108‧‧‧Flowmeter

FIG. 1 is a schematic diagram showing a configuration of a molten metal composition estimation device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of a molten metal component estimation process according to an embodiment of the present invention.

FIG. 3 is a graph showing an example of the relationship between the carbon concentration in the molten metal and the change rate of the luminous intensity, and the relationship between the carbon concentration in the molten metal and the decarburization oxygen efficiency.

Claims (5)

A molten metal composition estimating device is characterized in that: have: The input device is used to input measurement information about the refining equipment, and the measurement information includes: measurement results about the optical characteristics of the furnace mouth during the blowing process in the refining equipment; The model database stores model formulas and model parameters regarding the reaction of the refining process, and the model formulas and model parameters include the model formulas and models representing the relationship between the decarburization oxygen efficiency in the aforementioned refining equipment and the carbon concentration in the molten metal parameter; The model calculation unit estimates the component concentration of the molten metal including the carbon concentration in the molten metal using the measurement information, the model formula, and the model parameters; and The model determination unit estimates the carbon concentration in the molten metal based on the measurement result, and determines the model formula and the model parameter used by the model calculation unit based on the estimation result. For example, the molten metal component estimation device according to the first patent application range, wherein the measurement result includes a rate of change in intensity of a frequency spectrum caused by a reduction reaction of iron oxide in the slag. A method for estimating molten metal composition, which is characterized by: contain: The model calculation step uses: measurement information on the refining equipment including measurement results of the optical characteristics of the furnace mouth portion in the blowing process in the refining equipment; and information indicating the decarburization oxygen efficiency and molten metal in the refining equipment Model expressions and model parameters for the relationship between carbon concentrations. Model expressions and model parameters for the reaction of the blowing process, to estimate the component concentration of the molten metal including the carbon concentration in the molten metal; and The model determination step is to estimate the carbon concentration in the molten metal based on the measurement result, and to determine the model formula and the model parameter used in the model calculation step based on the estimation result. For example, the method for estimating a molten metal component according to item 3 of the application, wherein the measurement result includes a rate of change in intensity of a frequency spectrum caused by a reduction reaction of iron oxide in the slag. A method for manufacturing molten metal, which is characterized by: contain: A step of adjusting the component concentration of the molten metal to a desired range based on the component concentration of the molten metal estimated using the method for estimating the molten metal component according to item 3 or 4 of the patent application scope.